The present disclosure relates to a stacked chip device in which unit devices having different characteristics are combined to a single chip, and more particularly, to a stacked chip device undirected and having ensured reliability.
In an electronic device, representative passive devices include a resistor R, a capacitor C, and an inductor L, and functions and roles of these passive devices are various. For example, a resistor controls flow of a current flowing through a circuit and also plays a role of achieving impedance matching in an alternating current circuit. A capacitor basically plays a role of blocking a direct current and transmitting an alternating current signal, configures a time constant circuit, a delay circuit, an RC circuit, and an LC filter circuit, and removes noise for itself. An inductor performs functions of removing high frequency noise, and impedance matching.
In addition, due to varied resistance according to an applied voltage, a varistor device is widely used as a protection device for protecting important electronic components and circuits from overvoltage (a surge voltage) and static electricity. In other words, even though a current does not flow through a varistor device disposed inside a circuit, when overvoltage not smaller than a certain voltage or overvoltage due to lightening is applied on both terminals of the varistor, resistance of the varistor device rapidly decreases, almost all current flows through the varistor device and no current flows through other devices, and therefore the circuit is protected from the overvoltage. Such varistor devices are recently in a trend of being miniaturized and arrayed in order to protect a large-scale integrated circuit or the like from static electricity and overvoltage in response to miniaturization of electronic devices.
For example, important electronic components or circuits may be efficiently protected from overvoltage by combining the varistor device and a resistor device, and stable operation of the electronic components or circuits can be ensured by combining the varistor device and an inductor device to remove a noise component.
In such a way, when various unit devices are combined to one chip, a plurality of sheets are stacked in a vertical direction to manufacture a chip and conduction patterns including electrodes for realizing each device are formed on each sheet. At this point, a stacked chip device becomes to have directivity according to a horizontal arrangement or a vertical stack arrangement of unit devices. In other words, the stacked chip has directivity of different characteristics in the horizontal direction or the vertical direction. In this case, the stacked chip is required to be used in correspondence to the directivity when used in an electronic circuit, and a direction recognition mark is required to be indicated so that the directivity can be distinguished at the time of manufacturing the stacked chip. Accordingly, a manufacturing process becomes complex, caution is necessary in use thereof, and mounting task is delayed.
In addition, in the stacked chip device, a through-hole is formed which penetrates the conduction pattern on each sheet, and the conduction patterns are connected in a vertical direction by filling the through-hole with a conductor. At this point, since the chip is manufactured by stacking and compressing the plurality of sheets, stress is accumulated on a region where a through-hole is disposed, in particular, on a region where the through-hole is disposed in an overlapped manner, the conductor in the through-hole is modified, and a distance to a conduction pattern adjacent thereto becomes nearer than that originally designed. Accordingly, design characteristics of the stacked chip device are not properly realized. When the conductor in the through-hole becomes severely modified, electricity is partially concentrated to be short-circuited, to cause a leakage current, or to create a transient current.
Patent Literature 1: Korean Patent Laid-Open Publication No. 10-2011-0049200